Surface modification of polymeric membranes using plasma treatment: A comprehensive review

In the contemporary science era, polymer membranes have a wide range of services. Polymeric membranes have very good bulk properties having potential applications in various processing industries.These membranes can be even modified using various techniques. The surface modifications of membranes to incorporate various hydrophilic functional groups without changing the bulk properties has gained popularity. The surface becomes hydrophilic because new polar functional groups are formed. For instance, after oxygen and nitrogen plasma treatment (mostly used treatments), most common groups that are observed using FTIR (Fourier Transform Infrared Spectroscopy) are amide, amine, carbonyl and hydroxyl. However, during operation, the polymeric membrane tends to be fouled severely due to hydrophobicity of the material. Affecting factors of fouling areproperties of membrane (material, pore size and hydrophobicity), properties of solution (solidparticleconcentration, particle size and nature of components), and treatment conditions (flow rate, temperature, pH and pressure).Another instance, under oxygen plasma treatment, an adverse effect of etching takes place where oxygen tops in the order of etchants followed by nitrogen and trailed by argon, an inert gas, plasma, respectively, causing minor weight loss. This article reviews about non-equilibrium, low temperature physical and chemical surface modification of different types of co-polymeric membranes using plasma treatment and graft polymerization techniques to reduce membrane fouling.